Forward and reverse directions of the stop valve
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Generally, globe valves should be installed in accordance with the arrow indicated on the valve body (fluid entering from the lower side and exiting from the upper side). However, there are also cases where the arrow indicates the opposite direction (fluid entering from the upper side and exiting from the lower side). I have encountered such situations before, but assumed it was a manufacturing error and didn’t pay much attention to it. It is only recently that I learned that it is also possible to install them in this way. If the valve is designed to allow fluid to enter from the lower side and exit from the upper side, an incorrect installation can result in higher pressure being applied to the packing, leading to leaks. If the valve is designed for fluid to enter from the upper side and exit from the lower side, an incorrect installation can cause higher internal pressure within the valve, resulting in internal leaks. Of course, this applies to globe valves with a diameter of DN125 and high pressure levels. Do fellow experts agree with this?
I’ve heard similar claims. Installation must be carried out in accordance with the manufacturer’s instructions. It seems that high-pressure stop valves with fluid entering from the top and exiting from the bottom are becoming more common.
Mainly, it is to avoid high inlet and low outlet conditions; when the valve is closed, if the pressure difference is too large, the valve stem is subjected to excessive stress. Therefore, a design with high inlet and low outlet is adopted. There are many related discussions on this.
There are such options – high-pressure or large-diameter ones – and the manufacturer will take that into consideration for you.
Times are progressing, as they say; a large force is exerted when a stop valve is closed
Installation and construction must be carried out according to the PID diagram
After hearing what you said, our factory generally operates on a low-cost, high-profit basis.
Yes, generally it is low inlet and high outlet; however, it is also designed with the inlet at the top and the outlet at the bottom in order to improve sealing performance, or to prevent internal leakage as you mentioned~~
In some operating conditions, it is required that the stop valve be installed in reverse; specific details need to be checked
High in and low out is used for high-pressure situations; it is said that using low in and high out on high-pressure pipes can easily lead to internal leaks